Generally, bicycle frames are designed to be set up with either an electronic gear-shifting system, in which an electronic signal generated by an electronic gear-shift actuator is transmitted to an electronic gear shifter to effect gear changes, or a mechanical gear-shifting system, in which force is transmitted from a mechanical gear-shift actuator to a mechanical gear shifter by a traditional Bowden cable to effect gear changes. Electronic gear-shifting systems can be preferable, for example, in bicycle racing, in which increased responsiveness and fast gear changes are advantageous. Conversely, mechanical gear-shifting systems can be preferable, for example, when riding for long periods of time during which a battery for an electronic gear-shifting system cannot be easily replaced or recharged, or when riding in a location where service and/or replacement parts for sophisticated electronic gear-shifting systems are not available in the event of a component failure. However, bicycle frames designed to accept an electronic gear-shifting system cannot be easily converted to a mechanical gear-shifting system, and vice versa. Accordingly, improvements to bicycle frames are desirable.